diff --git a/MergePDFs.cs b/MergePDFs.cs
index 03ff9e2..d665a07 100644
--- a/MergePDFs.cs
+++ b/MergePDFs.cs
@@ -60,7 +60,7 @@
         }
         public static string[] CollectPdfFiles()
         {
-            string dirPath = ConfigurationManager.AppSettings["PDF-Path"];
+            string dirPath = ConfigurationManager.AppSettings["PDF-Path"] ?? "";
             Console.WriteLine(dirPath);
             string[] pdfFiles = Directory.EnumerateFiles(dirPath, "*.pdf").ToArray();
             Array.Sort(pdfFiles);
@@ -81,7 +81,7 @@
         public static string GetDate()
         {
             DateTime date = DateTime.Now;
-            string dateFormat = ConfigurationManager.AppSettings["dateFormat"];
+            string dateFormat = ConfigurationManager.AppSettings["dateFormat"] ?? "yyyy-MM-dd";
             return date.ToString(dateFormat);
         }
     }